Energy absorption comparison of conventional and dual gradient hierarchical multicellular tubes under axial impact

The bioinspired gradient hierarchical multicellular has been proved to have excellent crashworthiness performances. To further investigate the gradient effect on the crashworthiness characteristics of thin-walled tube, a dual gradient hierarchical multicellular tube (DGHMT) is proposed based on the micro and macro structural parameters of bamboo. The energy absorption performances among the dual gradient hierarchical multicellular tube, conventional square tube, multicellular tube (MT) and single gradient hierarchical multicellular tube (SGHMT) are systematically investigated. Results show that the crashworthiness performances of DGHMT are significantly better than other types of multicellular tubes under the same conditions. The maximum decrease of initial peak crushing force (IPCF) and the maximum increase of crush force efficiency (CFE) of DGHMT reach around 59% and 194%, respectively, compared with other tubes under the condition of same mass. Under the conditions of the same energy absorption and IPCF, the maximum decrease of IPCF and the maximum increase of CFE of DGHMT reach around 63% and 320%, respectively, compared with other tubes. These results can serve as guides for the structural design of energy absorber with dual hierarchical characteristics.